CN114337331B

CN114337331B - Three-phase power supply conversion circuit, circuit control method, circuit board and air conditioner

Info

Publication number: CN114337331B
Application number: CN202011066357.1A
Authority: CN
Inventors: 黄招彬; 龙谭; 赵鸣; 杨建宁; 徐锦清; 曾贤杰; 霍兆镜; 文先仕
Original assignee: GD Midea Air Conditioning Equipment Co Ltd; Chongqing Midea Refrigeration Equipment Co Ltd
Current assignee: GD Midea Air Conditioning Equipment Co Ltd; Chongqing Midea Refrigeration Equipment Co Ltd
Priority date: 2020-09-30
Filing date: 2020-09-30
Publication date: 2024-07-23
Anticipated expiration: 2040-09-30
Also published as: CN114337331A

Abstract

The invention discloses a three-phase power supply conversion circuit, a circuit control method, a circuit board and an air conditioner, wherein the three-phase power supply conversion circuit comprises a rectification module, an energy storage module, a control module and a direct current load module; the rectification module comprises a three-phase rectification bridge and a bidirectional switch assembly; the energy storage module comprises a first capacitor and a second capacitor; the direct current load module comprises at least two of a first direct current load, a second direct current load and a third load; the method comprises the steps of obtaining a current signal, a first capacitor voltage and a second capacitor voltage of a three-phase alternating current power supply, outputting a control signal to the bidirectional switch assembly according to at least two of the first target voltage of the first capacitor, the second target voltage of the second capacitor and the third target voltage of the energy storage module, so that voltages at two ends of corresponding loads are kept to be target voltages, stable voltages can be provided for the corresponding loads, three-phase currents of the three-phase alternating current power supply can be balanced, a phenomenon that current harmonic waves of a certain phase are obviously larger is avoided, and the harmonic waves can be effectively reduced.

Description

Three-phase power supply conversion circuit, circuit control method, circuit board and air conditioner

Technical Field

The invention relates to the technical field of air conditioners, in particular to a three-phase power supply conversion circuit, a circuit control method, a circuit board and an air conditioner.

Background

In the high-energy-efficiency variable-frequency air conditioning system powered by the three-phase power supply, besides the variable-frequency compressor load, a direct-current fan load is also arranged, and the air conditioning system is provided with one direct-current fan and two direct-current fans or even more. In the prior art, a three-phase power supply outputs high-voltage direct-current bus voltage after passing through a passive PFC rectifying circuit or a two-level active PFC rectifying circuit, and a variable-frequency compressor load is connected to the high-voltage direct-current bus voltage; the direct current fan load does not take power from the high-voltage direct current bus voltage, but is supplied with power after being rectified by another independent one-way phase voltage.

The reason for this design is that the IPM (I NTE L L IGENT Power Modu le ) module driving the dc fan is not voltage-tolerant enough and cannot directly draw power from the high-voltage dc bus. Normally, the effective value of the three-phase line voltage is 380V, and the rectified high-voltage direct-current bus voltage is 537V; plus 10% supply voltage fluctuation tolerance, the high voltage dc bus voltage will likely reach 590V; the dc bus voltage may further rise if active PFC control is employed. The withstand voltage of the high-voltage electrolytic capacitor is generally 450V or below, and in the application scene, the withstand voltage of the high-voltage electrolytic capacitor of the direct-current bus is required to be improved by adopting a two-stage series connection mode, and the two-stage series connection withstand voltage can reach 900V theoretically. The voltage resistance of the driving direct current fan IPM module is generally 500V or 600V, and the design requirement of the IPM module on voltage resistance is added, so that the input voltage of the direct current fan IPM module is generally below 450V. Because the voltage of the high-voltage direct-current bus is higher than the input voltage requirement of the IPM module of the direct-current fan, the direct power cannot be taken from the high-voltage direct-current bus.

In the prior art, an independent one-way phase voltage is adopted to rectify and then supply power to a direct-current fan load, so that the rectified direct-current voltage meets the voltage-withstanding requirement of an IPM module of the direct-current fan. But this also results in a higher load driving the direct current fan for this phase of power than the other two phases, and the increased part of the load does not pass through the two-level active PFC circuit, resulting in significantly greater current harmonics for this phase, unbalanced current signals for the three-phase ac power supply, and difficulty in meeting the iec (I nternat iona l E lectro TECHN ICA L Commi ss ion ) harmonic requirements.

Disclosure of Invention

The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

The invention aims to at least solve one of the technical problems in the prior art, and provides a three-phase power supply conversion circuit, a circuit control method, a circuit board and an air conditioner, which can provide stable voltage for corresponding loads, balance three-phase current and effectively reduce harmonic waves.

In a first aspect, an embodiment of the present invention provides a three-phase power conversion circuit, including a rectifying module, an energy storage module, a dc load module, and a control module;

The rectification module comprises a three-phase rectification bridge and a bidirectional switch assembly, wherein the three-phase rectification bridge comprises a first bridge arm, a second bridge arm and a third bridge arm which are mutually connected in parallel; the bidirectional switch assembly comprises a first bidirectional switch, a second bidirectional switch and a third bidirectional switch, one end of the first bidirectional switch is connected with the midpoint of the first bridge arm, one end of the second bidirectional switch is connected with the midpoint of the second bridge arm, and one end of the third bidirectional switch is connected with the midpoint of the third bridge arm;

The energy storage module is connected with the direct current output end of the rectifying module and comprises a first capacitor and a second capacitor which are connected in series, and the other end of the first bidirectional switch, the other end of the second bidirectional switch and the other end of the third bidirectional switch are connected between the first capacitor and the second capacitor;

The direct current load module comprises at least two of a first direct current load, a second direct current load and a third load, wherein the first direct current load is connected with the first capacitor in parallel, the second direct current load is connected with the second capacitor in parallel, and the third load is connected with the energy storage module in parallel;

The control module is connected with the bidirectional switch assembly and is used for acquiring current signals, first capacitor voltage and second capacitor voltage of the three-phase alternating current power supply, outputting control signals to the bidirectional switch assembly according to at least two of first target voltage of the first capacitor, second target voltage of the second capacitor and third target voltage of the energy storage module, so that voltages reaching two ends of the first capacitor are kept to be the first target voltage, voltages reaching two ends of the second capacitor are kept to be the second target voltage, and voltages reaching two ends of the energy storage module are kept to be at least two of the third target voltage.

The three-phase power supply conversion circuit provided by the embodiment of the invention has at least the following beneficial effects: the load conditions of the direct current load module can comprise various different combinations, such as a first direct current load plus a second direct current load, a first direct current load plus a third load, a second direct current load plus a third load, and a first direct current load plus a second direct current load plus a third load.

In the above three-phase power conversion circuit, the obtaining the current signal of the three-phase ac power, the first capacitor voltage and the second capacitor voltage, and outputting a control signal to the bidirectional switch assembly according to at least two of the first target voltage of the first capacitor, the second target voltage of the second capacitor, and the third target voltage of the energy storage module, so that the voltage reaching the two ends of the first capacitor is kept at the first target voltage, the voltage reaching the two ends of the second capacitor is kept at the second target voltage, and the voltage reaching the two ends of the energy storage module is kept at the third target voltage, respectively, includes:

When the difference value between the maximum phase voltage and the middle phase voltage of the three-phase alternating current power supply is smaller than a first voltage value and the difference value between the middle phase voltage and the minimum phase voltage of the three-phase alternating current power supply is smaller than a second voltage value, the control module controls the on-off of the bidirectional switch assembly according to a preset modulation strategy;

Wherein the preset modulation strategy is: the bidirectional switch corresponding to the intermediate phase voltage of the three-phase alternating current power supply is kept on, the bidirectional switch corresponding to the maximum phase voltage of the three-phase alternating current power supply is alternately turned on and off at a first duty ratio, the bidirectional switch corresponding to the minimum phase voltage of the three-phase alternating current power supply is alternately turned on and off at a second duty ratio, the first duty ratio is calculated according to the first target voltage, the first capacitor voltage and the current signal of the three-phase alternating current power supply, and the second duty ratio is calculated according to the second target voltage, the second capacitor voltage and the current signal of the three-phase alternating current power supply.

In the three-phase power supply conversion circuit, in a section in which a difference between a maximum phase voltage and an intermediate phase voltage of the three-phase ac power supply is smaller than a first voltage value and a difference between the intermediate phase voltage and a minimum phase voltage of the three-phase ac power supply is smaller than a second voltage value, the first bidirectional switch, the second bidirectional switch, and the third bidirectional switch are kept turned off.

In the three-phase power conversion circuit, in a section where a difference between a maximum phase voltage and an intermediate phase voltage of the three-phase ac power is smaller than a first voltage value and a difference between the intermediate phase voltage and a minimum phase voltage of the three-phase ac power is smaller than a second voltage value, a third duty ratio is calculated according to the third target voltage, the actual measurement value of the output voltage of the energy storage module and the current signal of the three-phase ac power so as to control the bidirectional switch assembly.

In the three-phase power conversion circuit, the first voltage value is a first target voltage of the first capacitor or the first capacitor voltage.

In the three-phase power conversion circuit, the second voltage value is a second target voltage of the second capacitor or the second capacitor voltage.

In the above three-phase power conversion circuit, the dc load module includes the first dc load and the second dc load, and the control module is specifically configured to:

And outputting a control signal to the bidirectional switch assembly according to the current signal of the three-phase alternating current power supply, the first capacitor voltage, the second capacitor voltage, the first target voltage of the first capacitor and the second target voltage of the second capacitor so as to enable the voltages at two ends of the first capacitor to be kept as the first target voltage and the voltages at two ends of the second capacitor to be kept as the second target voltage.

In the above three-phase power conversion circuit, the dc load module includes the first dc load and the third load, and the control module is specifically configured to:

and outputting a control signal to the bidirectional switch assembly according to the current signal of the three-phase alternating current power supply, the first capacitor voltage, the second capacitor voltage, the first target voltage of the first capacitor and the third target voltage of the energy storage module so as to enable the voltages at two ends of the first capacitor to be kept as the first target voltage and the voltages at two ends of the energy storage module to be kept as the third target voltage.

In the above three-phase power conversion circuit, the dc load module includes the second dc load and the third load, and the control module is specifically configured to:

And outputting a control signal to the bidirectional switch assembly according to the current signal of the three-phase alternating current power supply, the first capacitor voltage, the second target voltage of the second capacitor and the third target voltage of the energy storage module so as to enable the voltages at two ends of the second capacitor to be kept as the second target voltage and the voltages at two ends of the energy storage module to be kept as the third target voltage.

In the above three-phase power conversion circuit, the dc load module includes the first dc load, the second dc load, and the third load, and the control module is specifically configured to:

And outputting control signals to the bidirectional switch assembly according to the current signals of the three-phase alternating current power supply, the first capacitor voltage, the second capacitor voltage, the first target voltage of the first capacitor, the second target voltage of the second capacitor and the third target voltage of the energy storage module so as to enable the voltages at two ends of the first capacitor to be kept at the first target voltage, the voltages at two ends of the second capacitor to be kept at the second target voltage and the voltages at two ends of the energy storage module to be kept at the third target voltage.

In the three-phase power conversion circuit, the first bidirectional switch, the second bidirectional switch and the third bidirectional switch all comprise two power switching tubes which are connected in parallel in an anti-parallel mode.

In the three-phase power supply conversion circuit, the first bidirectional switch, the second bidirectional switch and the third bidirectional switch all comprise two power switch tubes which are reversely connected in series, and the two power switch tubes are reversely connected in parallel with diodes.

In the three-phase power supply conversion circuit, the first bidirectional switch, the second bidirectional switch and the third bidirectional switch respectively comprise a fourth bridge arm, a fifth bridge arm and a sixth bridge arm which are mutually connected in parallel, the fourth bridge arm and the sixth bridge arm respectively comprise two diodes which are mutually connected in series, and the fifth bridge arm comprises a power switch tube.

In a second aspect, an embodiment of the present invention provides a circuit control method, which is applied to a three-phase power conversion circuit, where the three-phase power conversion circuit includes a rectification module, an energy storage module and a dc load module, the rectification module includes a three-phase rectification bridge and a bidirectional switch assembly, and the three-phase rectification bridge includes a first bridge arm, a second bridge arm and a third bridge arm that are connected in parallel with each other; the bidirectional switch assembly comprises a first bidirectional switch, a second bidirectional switch and a third bidirectional switch, one end of the first bidirectional switch is connected with the midpoint of the first bridge arm, one end of the second bidirectional switch is connected with the midpoint of the second bridge arm, and one end of the third bidirectional switch is connected with the midpoint of the third bridge arm; the energy storage module is connected with the direct current output end of the rectifying module and comprises a first capacitor and a second capacitor which are connected in series, and the other end of the first bidirectional switch, the other end of the second bidirectional switch and the other end of the third bidirectional switch are connected between the first capacitor and the second capacitor; the direct current load module comprises at least two of a first direct current load, a second direct current load and a third load, wherein the first direct current load is connected with the first capacitor in parallel, the second direct current load is connected with the second capacitor in parallel, and the third load is connected with the energy storage module in parallel;

The circuit control method comprises the following steps:

And outputting control signals to the bidirectional switch assembly according to at least two of the first target voltage of the first capacitor, the second target voltage of the second capacitor and the third target voltage of the energy storage module, so that the voltages reaching the two ends of the first capacitor are kept to be at least two of the first target voltage, the voltages reaching the two ends of the second capacitor are kept to be the second target voltage and the voltages reaching the two ends of the energy storage module are kept to be the third target voltage.

The circuit control method provided by the embodiment of the invention has at least the following beneficial effects: the load conditions of the direct current load module can comprise various different combinations, such as a first direct current load plus a second direct current load, a first direct current load plus a third load, a second direct current load plus a third load, and a first direct current load plus a second direct current load plus a third load.

In the above circuit control method, the obtaining the current signal, the first capacitor voltage and the second capacitor voltage of the three-phase ac power supply, and outputting a control signal to the bidirectional switch assembly according to at least two of the first target voltage of the first capacitor, the second target voltage of the second capacitor, and the third target voltage of the energy storage module, so that the voltage reaching the two ends of the first capacitor is kept at the first target voltage, the voltage reaching the two ends of the second capacitor is kept at the second target voltage, and the voltage reaching the two ends of the energy storage module is kept at the third target voltage, respectively, includes:

When the difference value between the maximum phase voltage and the middle phase voltage of the three-phase alternating current power supply is smaller than a first voltage value, and the difference value between the middle phase voltage and the minimum phase voltage of the three-phase alternating current power supply is smaller than a second voltage value, controlling the on-off of the bidirectional switch component according to a preset modulation strategy;

In the circuit control method, in a section where a difference between a maximum phase voltage and a middle phase voltage of the three-phase alternating current power supply is smaller than a first voltage value and a difference between the middle phase voltage and a minimum phase voltage of the three-phase alternating current power supply is smaller than a second voltage value, the first bidirectional switch, the second bidirectional switch and the third bidirectional switch are kept turned off.

In the circuit control method, in a section where a difference between a maximum phase voltage and an intermediate phase voltage of the three-phase ac power supply is smaller than a first voltage value and a difference between the intermediate phase voltage and a minimum phase voltage of the three-phase ac power supply is smaller than a second voltage value, a third duty ratio is calculated according to the third target voltage, the actual measurement value of the output voltage of the energy storage module and the current signal of the three-phase ac power supply so as to control the bidirectional switch assembly.

In the above circuit control method, the first voltage value is a first target voltage of the first capacitor or the first capacitor voltage.

In the above circuit control method, the second voltage value is a second target voltage of the second capacitor or the second capacitor voltage.

In the above circuit control method, the dc load module includes the first dc load and the second dc load, and the circuit control method specifically includes:

In the above circuit control method, the dc load module includes the first dc load and the third load, and the circuit control method specifically includes:

In the above circuit control method, the dc load module includes the second dc load and the third load, and the circuit control method specifically includes:

In the above circuit control method, the dc load module includes the first dc load, the second dc load, and the third load, and the circuit control method specifically includes:

In a third aspect, an embodiment of the present invention provides a circuit board, including a three-phase power conversion circuit according to the embodiment of the first aspect of the present invention.

The circuit board provided by the embodiment of the invention has at least the following beneficial effects: the load conditions of the direct current load module can comprise various different combinations, such as a first direct current load plus a second direct current load, a first direct current load plus a third load, a second direct current load plus a third load, and a first direct current load plus a second direct current load plus a third load.

In a fourth aspect, an embodiment of the present invention provides an operation control device, including at least one processor and a memory for communication connection with the at least one processor; the memory stores instructions executable by the at least one processor to enable the at least one processor to perform a circuit control method according to an embodiment of the second aspect of the present invention.

The operation control device provided by the embodiment of the invention has at least the following beneficial effects: the load conditions of the direct current load module can comprise various different combinations, such as a first direct current load plus a second direct current load, a first direct current load plus a third load, a second direct current load plus a third load, and a first direct current load plus a second direct current load plus a third load.

In a fifth aspect, an embodiment of the present invention provides an air conditioner, including a circuit board according to an embodiment of the third aspect of the present invention or including an operation control device according to an embodiment of the fourth aspect of the present invention.

The air conditioner provided by the embodiment of the invention has at least the following beneficial effects: the load conditions of the direct current load module can comprise various different combinations, such as a first direct current load plus a second direct current load, a first direct current load plus a third load, a second direct current load plus a third load, and a first direct current load plus a second direct current load plus a third load.

In a sixth aspect, embodiments of the present invention provide a computer-readable storage medium storing computer-executable instructions for causing a computer to perform the circuit control method according to the embodiment of the second aspect of the present invention.

The computer readable storage medium provided according to the embodiment of the invention has at least the following beneficial effects: the load conditions of the direct current load module can comprise various different combinations, such as a first direct current load plus a second direct current load, a first direct current load plus a third load, a second direct current load plus a third load, and a first direct current load plus a second direct current load plus a third load.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate and do not limit the invention.

FIG. 1 is a schematic circuit diagram of a load case one of a three-phase power conversion circuit according to an embodiment of the present invention;

fig. 2 is a schematic circuit diagram of a load case two of a three-phase power conversion circuit according to an embodiment of the present invention;

FIG. 3 is a schematic circuit diagram of a three-phase power conversion circuit load case III according to an embodiment of the present invention;

FIG. 4 is a schematic circuit diagram of a load case four of a three-phase power conversion circuit according to an embodiment of the present invention;

Fig. 5 is a schematic diagram of a control strategy of a first control mode of the three-phase power conversion circuit according to an embodiment of the present invention;

fig. 6 is a control module structure diagram of a first control mode of the three-phase power conversion circuit according to the embodiment of the present invention;

Fig. 7 is a specific block diagram of a control module of a first control mode of the three-phase power conversion circuit according to the embodiment of the present invention;

Fig. 8 is a schematic diagram of a control strategy of a second control mode of the three-phase power conversion circuit according to the embodiment of the present invention;

fig. 9 is a control module structure diagram of a control mode two of a three-phase power conversion circuit according to an embodiment of the present invention;

fig. 10 is a specific block diagram of a control module of a control mode two of the three-phase power conversion circuit according to the embodiment of the present invention;

FIG. 11 is a specific block diagram of a bi-directional switch provided by one embodiment of the present invention;

FIG. 12 is a specific block diagram of a bi-directional switch provided by another embodiment of the present invention;

FIG. 13 is a specific block diagram of a bi-directional switch provided by yet another embodiment of the present invention;

fig. 14 is a block diagram of an operation control apparatus according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

It should be noted that although functional block division is performed in a device diagram and a logic sequence is shown in a flowchart, in some cases, the steps shown or described may be performed in a different order than the block division in the device, or in the flowchart. The terms first, second and the like in the description and in the claims and in the above-described figures, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

The invention provides a three-phase power supply conversion circuit, a circuit control method, a circuit board and an air conditioner, which can provide stable voltage for corresponding loads, balance current signals of a three-phase alternating current power supply and effectively reduce harmonic waves.

Embodiments of the present invention will be further described below with reference to the accompanying drawings.

Referring to fig. 1 to 4, an embodiment of a first aspect of the present invention provides a three-phase power conversion circuit, including a rectification module 100, an energy storage module 200, a control module, and a dc load module; the control module is not shown in fig. 1 to 4, but does not affect the understanding of the present embodiment.

The rectification module 100 comprises a three-phase rectification bridge 110 and a bidirectional switch assembly 120, wherein the three-phase rectification bridge 110 comprises a first bridge arm 111, a second bridge arm 112 and a third bridge arm 113 which are mutually connected in parallel, the first bridge arm 111 comprises a first diode D1 and a second diode D2 which are mutually connected in series, the second bridge arm 112 comprises a third diode D3 and a fourth diode D4 which are mutually connected in series, and the third bridge arm 113 comprises a fifth diode D5 and a sixth diode D6 which are mutually connected in series; it can be understood that, instead of two diodes connected in series, two switching tubes connected in series may be used for the first bridge arm 111, the second bridge arm 112 and the third bridge arm 113; the bidirectional switch assembly 120 includes a first bidirectional switch 121, a second bidirectional switch 122, and a third bidirectional switch 123, where one end of the first bidirectional switch 121 is connected to a midpoint of the first bridge arm 111, that is, a connection point a of the first diode D1 and the second diode D2, one end of the second bidirectional switch 122 is connected to a midpoint of the second bridge arm 112, that is, a connection point b of the third diode D3 and the fourth diode D4, and one end of the third bidirectional switch 123 is connected to a midpoint of the third bridge arm 113, that is, a connection point c of the fifth diode D5 and the sixth diode D6;

the energy storage module 200 is connected with the direct current output end of the rectifying module 100, the energy storage module 200 comprises a first capacitor C1 and a second capacitor C2 which are connected in series, and the other end of the first bidirectional switch 121, the other end of the second bidirectional switch 122 and the other end of the third bidirectional switch 123 are connected between the first capacitor C1 and the second capacitor C2; specifically, the dc output end of the rectifying module 100 includes a positive bus end d and a negative bus end e, one end of the first capacitor C1 is connected to the positive bus end d, one end of the second capacitor C2 is connected to the negative bus end e, the other end of the first capacitor C1 and the other end of the second capacitor C2 are connected together, a connection point between the first capacitor C1 and the second capacitor C2 is a dc bus midpoint f, and the other end of the first bidirectional switch 121, the other end of the second bidirectional switch 122, and the other end of the third bidirectional switch 123 are all connected to the dc bus midpoint f;

In addition, the three-phase ac power supply includes an a-phase voltage, a B-phase voltage, and a C-phase voltage, the a-phase voltage being connected to a connection point a of the first diode D1 and the second diode D2 through the first inductor L1, the B-phase voltage being connected to a connection point B of the third diode D3 and the fourth diode D4 through the second inductor L2, the C-phase voltage being connected to a connection point C of the fifth diode D5 and the sixth diode D6 through the third inductor L3;

The direct current load module comprises at least two of a first direct current load, a second direct current load and a third load, wherein the first direct current load is connected with the first capacitor C1 in parallel, the second direct current load is connected with the second capacitor C2 in parallel, and the third load is connected with the energy storage module 200 in parallel; specifically, the load conditions of the three-phase power supply conversion circuit are as follows: the first type is shown in fig. 1, and comprises a first direct current load, a second direct current load and a third load; the second, as shown in fig. 2, includes a first dc load and a third load; the third is shown in fig. 3, and comprises a second direct current load and a third load; a fourth, as shown in fig. 4, comprising a first dc load and a second dc load;

The control module is connected with the bidirectional switch assembly 120, namely, the control module is respectively connected with the first bidirectional switch 121, the second bidirectional switch 122 and the third bidirectional switch 123; the control module is configured to obtain a current signal iabc of the three-phase ac power supply, a first capacitor voltage U1, and a second capacitor voltage U2, and output a control signal to the bidirectional switch assembly 120 according to at least two of a first target voltage U1 ref of the first capacitor C1, a second target voltage U2ref of the second capacitor C2, and a third target voltage Udcref of the energy storage module 200, so that voltages reaching two ends of the first capacitor C1 are maintained as the first target voltage U1 ref, voltages reaching two ends of the second capacitor C2 are maintained as the second target voltage U2ref, and voltages reaching two ends of the energy storage module 200 are maintained as the third target voltage Udcref.

It should be noted that, the current signal iabc of the three-phase ac power supply may be obtained by directly detecting a three-phase current signal of the three-phase ac power supply; alternatively, any two-phase current signal of the three-phase ac power supply may be detected, and then the third-phase current signal may be calculated, thereby obtaining the current signal iabc of the three-phase ac power supply.

It can be understood that, when the load condition of the three-phase power conversion circuit is the condition shown in fig. 1, that is, the dc load module includes a first dc load, a second dc load and a third load, the control module is specifically configured to: acquiring a current signal iabc, a first capacitor voltage U1 and a second capacitor voltage U2 of the three-phase alternating-current power supply, and correspondingly outputting control signals to the bidirectional switch assembly 120 according to the current signal iabc, the first capacitor voltage U1, the second capacitor voltage U2, a first target voltage U1 ref of the first capacitor C1, a second target voltage U2ref of the second capacitor C2 and a third target voltage Udcref of the energy storage module 200 of the three-phase alternating-current power supply, so that voltages at two ends of the first capacitor C1 are kept to be the first target voltage U1 ref, voltages at two ends of the second capacitor C2 are kept to be the second target voltage U2ref, and voltages at two ends of the energy storage module 200 are kept to be the third target voltage Udcref;

When the load condition of the three-phase power conversion circuit is the condition shown in fig. 2, that is, the dc load module includes a first dc load and a third load, the control module is specifically configured to: acquiring a current signal iabc, a first capacitor voltage U1 and a second capacitor voltage U2 of the three-phase alternating-current power supply, and correspondingly outputting control signals to the bidirectional switch assembly 120 according to the current signal iabc, the first capacitor voltage U1, the second capacitor voltage U2, a first target voltage U1 ref of the first capacitor C1 and a third target voltage Udcref of the energy storage module 200 of the three-phase alternating-current power supply, so that voltages at two ends of the first capacitor C1 are kept to be the first target voltage U1 ref and voltages at two ends of the energy storage module 200 are kept to be the third target voltage Udcref;

When the load condition of the three-phase power conversion circuit is the condition shown in fig. 3, that is, the dc load module includes a second dc load and a third load, the control module is specifically configured to: acquiring a current signal iabc, a first capacitor voltage U1 and a second capacitor voltage U2 of the three-phase alternating-current power supply, and correspondingly outputting control signals to the bidirectional switch assembly 120 according to the current signal iabc, the first capacitor voltage U1, the second capacitor voltage U2, a second target voltage U2ref of the second capacitor C2 and a third target voltage Udcref of the energy storage module 200 of the three-phase alternating-current power supply, so that voltages at two ends of the second capacitor C2 are kept to be the second target voltage U2ref and voltages at two ends of the energy storage module 200 are kept to be the third target voltage Udcref;

when the load condition of the three-phase power conversion circuit is the condition shown in fig. 4, that is, the dc load module includes a first dc load and a second dc load, the control module is specifically configured to: the method comprises the steps of obtaining a current signal iabc of a three-phase alternating-current power supply, a first capacitor voltage U1 and a second capacitor voltage U2, and correspondingly outputting control signals to the bidirectional switch assembly 120 according to the current signal iabc of the three-phase alternating-current power supply, the first capacitor voltage U1, the second capacitor voltage U2, a first target voltage U1 ref of the first capacitor C1 and a second target voltage U2ref of the second capacitor C2, so that voltages at two ends of the first capacitor C1 are kept to be the first target voltage U1 ref, and voltages at two ends of the second capacitor C2 are kept to be the second target voltage U2ref.

Specifically, in the three-phase power conversion circuit, for all load situations, there are two control strategies that the control module can use, hereinafter referred to as a first control mode and a second control mode, respectively.

Referring to fig. 5, for the first control mode, specifically:

The control module controls the on-off of the bidirectional switch assembly 120 with a first preset modulation strategy in a preset working interval; the preset working interval is an interval in which the difference value between the maximum phase voltage and the intermediate phase voltage of the three-phase alternating current power supply is smaller than a first voltage value Uh igh, and the difference value between the intermediate phase voltage and the minimum phase voltage of the three-phase alternating current power supply is smaller than a second voltage value U low;

The first preset modulation strategy is: the bidirectional switch corresponding to the intermediate phase voltage of the three-phase alternating current power supply is kept on, the bidirectional switch corresponding to the maximum phase voltage of the three-phase alternating current power supply is alternately turned on and off at a first duty ratio Dmax, the bidirectional switch corresponding to the minimum phase voltage of the three-phase alternating current power supply is alternately turned on and off at a second duty ratio Dmin, wherein the first duty ratio Dmax is calculated according to a first target voltage U1 ref of a first capacitor C1, a first capacitor voltage U1 and a current signal iabc of the three-phase alternating current power supply, and the second duty ratio Dmin is calculated according to a second target voltage U2ref of a second capacitor C2, a second capacitor voltage U2 and a current signal iabc of the three-phase alternating current power supply.

The maximum phase voltage, the intermediate phase voltage and the minimum phase voltage of the three-phase alternating current power supply are determined according to the voltage amplitude at the current moment, for example, at a certain moment or in a certain continuous time period, the maximum phase voltage of the three-phase alternating current power supply is the A phase voltage, the intermediate phase voltage is the B phase voltage, and the minimum phase voltage is the C phase voltage; at the next moment or in the next continuous time period, the maximum phase voltage of the three-phase alternating current power supply is B-phase voltage, the intermediate phase voltage is A-phase voltage, and the minimum phase voltage is C-phase voltage; and the next moment or the next continuous time period, the maximum phase voltage of the three-phase alternating current power supply is B-phase voltage, the intermediate phase voltage is C-phase voltage, and the minimum phase voltage is A-phase voltage. Other things and so on.

Specifically, as shown in fig. 6, the control module includes a first controller, a second controller and a modulation module, where the first controller calculates a first duty ratio Dmax of the bidirectional switch corresponding to a maximum phase voltage of the three-phase ac power supply according to the first capacitor voltage U1, the first target voltage U1 ref and a current signal iabc of the three-phase ac power supply; the second controller calculates a second duty ratio Dmin of the bidirectional switch corresponding to the minimum phase voltage of the three-phase alternating current power supply according to the second capacitor voltage U2, the second target voltage U2ref and the current signal iabc of the three-phase alternating current power supply; the duty ratio Dmid of the bidirectional switch corresponding to the intermediate phase voltage of the three-phase alternating current power supply is kept to be 1; the modulation module modulates according to Dmax, dmid and Dmin and outputs a corresponding PWM signal to the bidirectional switch assembly 120 to implement a first preset modulation strategy.

More specifically, fig. 7 shows a specific embodiment of the control module implementing the first preset modulation strategy. The control module comprises a first voltage control loop, a second voltage control loop, a first current control loop, a second current control loop, a three-phase current decomposition module and a modulation module. The first voltage control loop is formed by a PI controller, and is given as a first target voltage U1 ref, fed back as a first capacitor voltage U1, and a reference compensation current ixref in a preset working interval is calculated; the three-phase current decomposition module acquires a current signal iabc of the three-phase alternating current power supply, takes a current corresponding to the maximum phase voltage of the three-phase alternating current power supply as a maximum opposite feed current ix, and takes a current corresponding to the minimum phase voltage of the three-phase alternating current power supply as a minimum phase feedback current in; the first current control loop is composed of a PI controller, the PI controller gives a reference compensation current ixref, the feedback is a maximum opposite feed current ix, and a bidirectional switch corresponding to the maximum phase voltage is calculated and obtained to have a first duty ratio Dmax; the second voltage control loop is formed by a PI controller, and is given as a second target voltage U2ref, fed back as a second capacitor voltage U2, and a reference compensation current inref in a preset working interval is calculated; the second current control loop is composed of a PI controller, the PI controller gives a reference compensation current inref, the feedback is a minimum phase feedback current in, and a bidirectional switch corresponding to the minimum phase voltage is calculated to obtain a second duty ratio Dmin; the duty ratio Dmid of the bidirectional switch corresponding to the intermediate phase voltage is kept to be 1; the modulation module modulates according to Dmax, dmid and Dmin and outputs a corresponding PWM signal to the bidirectional switch assembly 120 to implement a first preset modulation strategy.

For control mode one, the duty cycles of all of the bi-directional switches of bi-directional switch assembly 120 are replaced with 0, i.e., all remain off, during time intervals other than the preset operating interval.

Referring to fig. 8, for the second control method, specifically:

The control module controls the on-off of the bidirectional switch assembly 120 by a second preset modulation strategy in a preset working interval, and controls the on-off of the bidirectional switch assembly 120 by a third preset modulation strategy outside the preset working interval; the preset working interval is an interval in which the difference value between the maximum phase voltage and the intermediate phase voltage of the three-phase alternating current power supply is smaller than a first voltage value Uh igh, and the difference value between the intermediate phase voltage and the minimum phase voltage of the three-phase alternating current power supply is smaller than a second voltage value U low;

The second preset modulation strategy is: the bidirectional switch corresponding to the intermediate phase voltage of the three-phase alternating current power supply is kept on, the bidirectional switch corresponding to the maximum phase voltage of the three-phase alternating current power supply is alternately turned on and off at a first duty ratio Dmax, the bidirectional switch corresponding to the minimum phase voltage of the three-phase alternating current power supply is alternately turned on and off at a second duty ratio Dmin, wherein the first duty ratio Dmax is calculated according to a first target voltage U1 ref of a first capacitor C1, the first capacitor voltage U1, a current signal iabc of the three-phase alternating current power supply and a current signal reference value iabcref of the three-phase alternating current power supply, and the second duty ratio Dmin is calculated according to a second target voltage U2ref of a second capacitor C2, a second capacitor voltage U2, a current signal iabc of the three-phase alternating current power supply and a current signal reference value iabcref of the three-phase alternating current power supply;

the third preset modulation strategy is: a third duty cycle is calculated from the third target voltage Udcref, the measured value Udc of the output voltage of the energy storage module 200 and the current signal iabc of the three-phase ac power supply to control the bi-directional switching assembly.

Specifically, as shown in fig. 9, the control module includes a first control module portion, a second control module portion, a three-phase current decomposition module, a complementary current increment calculation module, and a modulation module, where the first control module portion is configured to generate a first duty ratio Dmax and a second duty ratio Dmin corresponding to a second preset modulation strategy in a preset working interval, and the second control module portion is configured to generate a third duty ratio corresponding to a third preset modulation strategy outside the preset working interval; the three-phase current decomposition module acquires a current signal iabc of the three-phase alternating current power supply, takes a current corresponding to the maximum phase voltage of the three-phase alternating current power supply as a maximum opposite feed current ix, takes a current corresponding to the minimum phase voltage of the three-phase alternating current power supply as a minimum phase feedback current in, and transmits the maximum opposite feed current ix and the minimum phase feedback current in to the first control module; the supplementary current increment calculation module obtains a current signal reference value iabcref of the three-phase alternating current power supply, takes the current corresponding to the maximum phase voltage of the three-phase alternating current power supply as a maximum phase compensation current increment Deltaix, takes the current corresponding to the minimum phase voltage of the three-phase alternating current power supply as a minimum phase compensation current increment Delta i n, and transmits the maximum phase compensation current increment Deltaix and the minimum phase compensation current increment Deltain to the first control module;

The first control module part comprises a first voltage control loop, a second voltage control loop, a first current control loop and a second current control loop, wherein the first voltage control loop is formed by a PI controller, the first voltage control loop is given as a first target voltage U1 ref, feedback is a first capacitor voltage U1, and the maximum phase current compensation quantity ixref in a preset working interval is calculated; the first current control loop is composed of a PI controller, and calculates a first duty ratio Dmax according to a maximum phase current compensation quantity ixref, a maximum phase compensation current increment Deltaix and a maximum opposite feed current ix; the second voltage control loop is formed by a PI controller, and is given as a second target voltage U2ref, fed back as a second capacitor voltage U2, and the minimum phase current compensation amount inref in a preset working interval is calculated; the second current control loop is formed by a PI controller, and calculates a second duty ratio Dmin according to the minimum phase current compensation amount inref, the minimum phase compensation current increment delta in and the minimum phase feedback current in; in addition, the first control module section also sets the duty ratio Dmid of the bidirectional switch corresponding to the intermediate phase voltage of the three-phase alternating current power supply to 1.

Specifically, as shown in fig. 10, after the three-phase current decomposition module obtains the current signal iabc of the three-phase ac power supply, the three-phase current decomposition module also decomposes the balance current ipabc corresponding to the three-phase balance load, and transmits the balance current ipabc to the second control module, and the second control module calculates the third duty ratio to control the bidirectional switch component according to the balance current ipabc, the third target voltage Udcref, and the actual measurement value Udc of the output voltage of the energy storage module 200, where the principle of calculating the third duty ratio by the second control module belongs to the prior art and is not repeated herein.

The modulation module acquires a first duty ratio Dmax, a second duty ratio Dmin and a duty ratio Dmid corresponding to a second preset modulation strategy in a preset working interval from the first control module part, acquires a third duty ratio corresponding to a third preset modulation outside the preset working interval from the second control module part, and modulates out a control signal of the whole period of the bidirectional switch component.

In the three-phase power conversion circuit, the first voltage value uhigh may be the first target voltage U1 ref of the first capacitor C1 or the first capacitor voltage U1; the second voltage value ulow is the second target voltage U2ref of the second capacitor C2 or the second capacitor voltage U2.

In the three-phase power conversion circuits of fig. 1 to 4, the first bi-directional switch 121, the second bi-directional switch 122 and the third bi-directional switch 123 each include two power switching transistors connected in anti-parallel, as shown in fig. 11.

The bidirectional switch formed by two power switch tubes connected in reverse parallel is a full-control bidirectional conduction power switch, and can realize bidirectional conduction through control signals or bidirectional blocking through control signals. Specifically, the two power switching tubes are controlled to be conducted simultaneously, namely, the two-way conduction is achieved, and the two power switching tubes are controlled to be turned off simultaneously, namely, the two-way blocking is achieved.

In the three-phase power conversion circuit of fig. 1 to 4, the first bidirectional switch 121, the second bidirectional switch 122 and the third bidirectional switch 123 may be replaced by two power switching transistors connected in reverse series, and the two power switching transistors are connected in reverse parallel with diodes, as shown in fig. 12.

The bidirectional switch formed by the power switch tubes which are connected in reverse series and provided with the anti-parallel diodes is a full-control bidirectional conduction power switch, and can realize bidirectional conduction through control signals and bidirectional blocking through control signals. Specifically, the two power switching tubes are controlled to be conducted simultaneously, namely, the two-way conduction is achieved, and the two power switching tubes are controlled to be turned off simultaneously, namely, the two-way blocking is achieved. In addition, the diode can be a fast recovery diode.

In the three-phase power conversion circuits of fig. 1 to 4, the first bidirectional switch 121, the second bidirectional switch 122, and the third bidirectional switch 123 each include a fourth leg, a fifth leg, and a sixth leg that are connected in parallel, each of the fourth leg and the sixth leg includes two diodes connected in series with each other, the fifth leg includes a power switching tube, as shown in fig. 13, the fourth leg includes a diode D7 and a diode D8 connected in series with each other, the fifth leg includes a power switching tube Q1, and the sixth leg includes a diode D9 and a diode D10 connected in series with each other. The forward conduction of the first bidirectional switch 121, the second bidirectional switch 122 and the third bidirectional switch 123 is the circulation direction of the diode D7-power switch Q1-diode D8, and the reverse conduction of the first bidirectional switch 121, the second bidirectional switch 122 and the third bidirectional switch 123 is the circulation direction of the diode D9-power switch Q1-diode D10; when the power switch Q1 is turned off, the first, second and third bidirectional switches 121, 122 and 123 are in a bidirectional blocking state.

In a second aspect, an embodiment of the present invention provides a circuit control method, which is applied to a three-phase power conversion circuit as shown in fig. 1 to 4, where the three-phase power conversion circuit includes a rectification module 100, an energy storage module 200, a dc load module, and a control module, the rectification module 100 includes a three-phase rectification bridge 110 and a bidirectional switch assembly 120, and the three-phase rectification bridge 110 includes a first bridge arm 111, a second bridge arm 112, and a third bridge arm 113 that are connected in parallel with each other; the bidirectional switch assembly 120 comprises a first bidirectional switch 121, a second bidirectional switch 122 and a third bidirectional switch 123, wherein one end of the first bidirectional switch 121 is connected with the midpoint of the first bridge arm 111, one end of the second bidirectional switch 122 is connected with the midpoint of the second bridge arm 112, and one end of the third bidirectional switch 123 is connected with the midpoint of the third bridge arm 113; the energy storage module 200 is connected with the direct current output end of the rectifying module 100, the energy storage module 200 comprises a first capacitor C1 and a second capacitor C2 which are connected in series, and the other end of the first bidirectional switch 121, the other end of the second bidirectional switch 122 and the other end of the third bidirectional switch 123 are connected between the first capacitor C1 and the second capacitor C2; the direct current load module comprises at least two of a first direct current load, a second direct current load and a third load, wherein the first direct current load is connected with the first capacitor C1 in parallel, the second direct current load is connected with the second capacitor C2 in parallel, and the third load is connected with the energy storage module 200 in parallel; the control module is connected with the bidirectional switch assembly 120, namely, the control module is respectively connected with the first bidirectional switch 121, the second bidirectional switch 122 and the third bidirectional switch 123;

The circuit control method comprises the following steps:

and acquiring a current signal iabc, a first capacitor voltage U1 and a second capacitor voltage U2 of the three-phase alternating current power supply, and outputting a control signal to the bidirectional switch assembly 120 according to at least two of a first target voltage U1 ref of the first capacitor C1, a second target voltage U2ref of the second capacitor C2 and a third target voltage Udcref of the energy storage module 200 respectively, so that the voltages reaching the two ends of the first capacitor C1 respectively are kept as the first target voltage U1 ref, the voltages at the two ends of the second capacitor C2 are kept as the second target voltage U2ref, and the voltages at the two ends of the energy storage module 200 respectively are kept as the third target voltage Udcref.

The load conditions of the three-phase power supply conversion circuit are as follows: the first type is shown in fig. 1, and comprises a first direct current load, a second direct current load and a third load; the second, as shown in fig. 2, includes a first dc load and a third load; the third is shown in fig. 3, and comprises a second direct current load and a third load; the fourth, as shown in fig. 4, includes a first dc load and a second dc load.

Correspondingly, when the load condition of the three-phase power conversion circuit is the condition shown in fig. 1, that is, the direct current load module includes a first direct current load, a second direct current load and a third load, the circuit control method specifically includes: acquiring a current signal iabc, a first capacitor voltage U1 and a second capacitor voltage U2 of the three-phase alternating-current power supply, and correspondingly outputting control signals to the bidirectional switch assembly 120 according to the current signal iabc, the first capacitor voltage U1, the second capacitor voltage U2, a first target voltage U1 ref of the first capacitor C1, a second target voltage U2ref of the second capacitor C2 and a third target voltage Udcref of the energy storage module 200 of the three-phase alternating-current power supply, so that voltages at two ends of the first capacitor C1 are kept to be the first target voltage U1 ref, voltages at two ends of the second capacitor C2 are kept to be the second target voltage U2ref, and voltages at two ends of the energy storage module 200 are kept to be the third target voltage Udcref;

When the load condition of the three-phase power conversion circuit is the condition shown in fig. 2, that is, the direct current load module includes a first direct current load and a third load, the circuit control method specifically includes: acquiring a current signal iabc, a first capacitor voltage U1 and a second capacitor voltage U2 of the three-phase alternating-current power supply, and correspondingly outputting control signals to the bidirectional switch assembly 120 according to the current signal iabc, the first capacitor voltage U1, the second capacitor voltage U2, a first target voltage U1 ref of the first capacitor C1 and a third target voltage Udcref of the energy storage module 200 of the three-phase alternating-current power supply, so that voltages at two ends of the first capacitor C1 are kept to be the first target voltage U1 ref and voltages at two ends of the energy storage module 200 are kept to be the third target voltage Udcref;

When the load condition of the three-phase power conversion circuit is the condition shown in fig. 3, that is, the direct current load module includes a second direct current load and a third load, the circuit control method specifically includes: acquiring a current signal iabc, a first capacitor voltage U1 and a second capacitor voltage U2 of the three-phase alternating-current power supply, and correspondingly outputting control signals to the bidirectional switch assembly 120 according to the current signal iabc, the first capacitor voltage U1, the second capacitor voltage U2, a second target voltage U2ref of the second capacitor C2 and a third target voltage Udcref of the energy storage module 200 of the three-phase alternating-current power supply, so that voltages at two ends of the second capacitor C2 are kept to be the second target voltage U2ref and voltages at two ends of the energy storage module 200 are kept to be the third target voltage Udcref;

When the load condition of the three-phase power conversion circuit is the condition shown in fig. 4, that is, the direct current load module includes a first direct current load and a second direct current load, the circuit control method specifically includes: the method comprises the steps of obtaining a current signal iabc of a three-phase alternating-current power supply, a first capacitor voltage U1 and a second capacitor voltage U2, and correspondingly outputting control signals to the bidirectional switch assembly 120 according to the current signal iabc of the three-phase alternating-current power supply, the first capacitor voltage U1, the second capacitor voltage U2, a first target voltage U1 ref of the first capacitor C1 and a second target voltage U2ref of the second capacitor C2, so that voltages at two ends of the first capacitor C1 are kept to be the first target voltage U1 ref, and voltages at two ends of the second capacitor C2 are kept to be the second target voltage U2ref.

Specifically, in the above-mentioned circuit control method, there are two control strategies that can be adopted for all load situations, and they are hereinafter referred to as a first control mode and a second control mode, respectively.

Referring to fig. 5, for the first control mode, specifically:

Referring to fig. 8, for the second control method, specifically:

Specifically, as shown in fig. 9, the control module includes a first control module portion, a second control module portion, a three-phase current decomposition module, a complementary current increment calculation module, and a modulation module, where the first control module portion is configured to generate a first duty ratio Dmax and a second duty ratio Dmin corresponding to a second preset modulation strategy in a preset working interval, and the second control module portion is configured to generate a third duty ratio corresponding to a third preset modulation strategy outside the preset working interval; the three-phase current decomposition module acquires a current signal iabc of the three-phase alternating current power supply, takes a current corresponding to the maximum phase voltage of the three-phase alternating current power supply as a maximum opposite feed current ix, takes a current corresponding to the minimum phase voltage of the three-phase alternating current power supply as a minimum phase feedback current in, and transmits the maximum opposite feed current ix and the minimum phase feedback current in to the first control module; the supplementary current increment calculation module obtains a current signal reference value iabcref of the three-phase alternating current power supply, takes the current corresponding to the maximum phase voltage of the three-phase alternating current power supply as a maximum phase compensation current increment Deltaix, takes the current corresponding to the minimum phase voltage of the three-phase alternating current power supply as a minimum phase compensation current increment Deltain, and transmits the maximum phase compensation current increment Deltaix and the minimum phase compensation current increment Deltain to the first control module;

In a third aspect, an embodiment of the present invention provides a circuit board, including a three-phase power conversion circuit according to an embodiment of the first aspect of the present invention.

According to the circuit board provided by the embodiment of the invention, the load condition of the direct current load module can comprise various different combinations, such as a first direct current load plus a second direct current load, a first direct current load plus a third load, a second direct current load plus a third load, and a first direct current load plus a second direct current load plus a third load, for each load condition, by obtaining the current signal iabc, the first capacitor voltage U1 and the second capacitor voltage U2 of the three-phase alternating current power supply and outputting a control signal to the bidirectional switch assembly 120 according to the target voltage of the corresponding load, the first bidirectional switch 121, the second bidirectional switch 122 and the third bidirectional switch 123 are controlled, so that the voltage at two ends of the corresponding load is kept to be the target voltage, thereby providing stable voltage to the corresponding load, balancing the three-phase current of the three-phase alternating current power supply, avoiding that the current harmonic of a certain phase is obviously larger, and effectively reducing the harmonic.

Fourth aspect referring to fig. 14, an embodiment of the present invention provides an operation control apparatus 100 including at least one processor 110 and a memory 120 for communicatively coupling with the at least one processor 110; the memory 120 stores instructions executable by the at least one processor 110 to enable the at least one processor 710 to perform a circuit control method as an embodiment of the second aspect of the present invention.

According to the operation control device 100 provided in the embodiment of the present invention, the load condition of the dc load module may include various combinations, for example, a first dc load plus a second dc load, a first dc load plus a third load, a second dc load plus a third load, and a first dc load plus a second dc load plus a third load, and for each load condition, by obtaining the current signal iabc, the first capacitor voltage U1, and the second capacitor voltage U2 of the three-phase ac power supply, and according to the target voltages of the corresponding loads, a control signal is output to the bidirectional switch assembly 120, and the first bidirectional switch 121, the second bidirectional switch 122, and the third bidirectional switch 123 are controlled, so that the voltages at both ends of the corresponding loads are kept to be the target voltages thereof, thereby providing a stable voltage to the corresponding loads, balancing the three-phase currents of the three-phase ac power supply, avoiding that the current harmonics of a phase are significantly larger, and effectively reducing the harmonics.

In a fifth aspect, an embodiment of the present invention provides an air conditioner including a circuit board as in the embodiment of the third aspect of the present invention or including an operation control device 100 as in the embodiment of the fourth aspect of the present invention.

According to the air conditioner provided by the embodiment of the invention, the load condition of the direct current load module can comprise various different combinations, such as a first direct current load plus a second direct current load, a first direct current load plus a third load, a second direct current load plus a third load, and a first direct current load plus a second direct current load plus a third load, for each load condition, by obtaining a current signal iabc, a first capacitor voltage U1 and a second capacitor voltage U2 of the three-phase alternating current power supply and outputting a control signal to the bidirectional switch assembly 120 according to the target voltage of the corresponding load, the first bidirectional switch 121, the second bidirectional switch 122 and the third bidirectional switch 123 are controlled, so that the voltage at two ends of the corresponding load is kept to be the target voltage, thereby stable voltage can be provided to the corresponding load, three-phase current of the three-phase alternating current power supply can be balanced, harmonic waves of a certain phase current are avoided to be obviously larger, and harmonic waves can be effectively reduced.

In a sixth aspect, embodiments of the present invention provide a computer-readable storage medium storing computer-executable instructions for causing a computer to perform a circuit control method as in the embodiments of the second aspect of the present invention.

According to the computer readable storage medium provided by the embodiment of the invention, the load condition of the dc load module may include a plurality of different combinations, for example, a first dc load plus a second dc load, a first dc load plus a third load, a second dc load plus a third load, a first dc load plus a second dc load plus a third load, and for each load condition, by obtaining the current signal iabc, the first capacitor voltage U1, and the second capacitor voltage U2 of the three-phase ac power supply, and according to the target voltage of the corresponding load, outputting a control signal to the bidirectional switch assembly 120, and controlling the first bidirectional switch 121, the second bidirectional switch 122, and the third bidirectional switch 123, the voltage at both ends of the corresponding load is kept to be the target voltage thereof, so that a stable voltage can be provided to the corresponding load, and the three-phase current of the three-phase ac power supply can be balanced, the current harmonic of a phase is avoided from being significantly larger, and the harmonic can be effectively reduced.

Those of ordinary skill in the art will appreciate that all or some of the steps, systems, and methods disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on computer readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). The term computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, as known to those skilled in the art. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer. Furthermore, as is well known to those of ordinary skill in the art, communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of one of ordinary skill in the art without departing from the spirit of the present invention.

Claims

1. A three-phase power conversion circuit, comprising:

The three-phase rectifying bridge comprises a first bridge arm, a second bridge arm and a third bridge arm which are mutually connected in parallel; the bidirectional switch assembly comprises a first bidirectional switch, a second bidirectional switch and a third bidirectional switch, one end of the first bidirectional switch is connected with the midpoint of the first bridge arm, one end of the second bidirectional switch is connected with the midpoint of the second bridge arm, and one end of the third bidirectional switch is connected with the midpoint of the third bridge arm;

The energy storage module is connected with the direct current output end of the rectifying module and comprises a first capacitor and a second capacitor which are mutually connected in series, and the other end of the first bidirectional switch, the other end of the second bidirectional switch and the other end of the third bidirectional switch are all connected between the first capacitor and the second capacitor;

the control module is connected with the bidirectional switch assembly and is used for acquiring current signals, first capacitor voltage and second capacitor voltage of the three-phase alternating current power supply, outputting control signals to the bidirectional switch assembly according to at least two of the first target voltage of the first capacitor, the second target voltage of the second capacitor and the third target voltage of the energy storage module, so that the voltages reaching the two ends of the first capacitor are kept to be the first target voltage, the voltages at the two ends of the second capacitor are kept to be the second target voltage, and the voltages at the two ends of the energy storage module are kept to be at least two of the third target voltage.

2. The three-phase power conversion circuit according to claim 1, wherein the obtaining the current signal of the three-phase ac power, the first capacitor voltage, and the second capacitor voltage, and outputting a control signal to the bidirectional switch assembly so that the voltage reaching the first capacitor is maintained at least two of the first target voltage, the voltage reaching the second capacitor is maintained at the second target voltage, and the voltage reaching the energy storage module is maintained at the third target voltage, respectively, according to at least two of the first target voltage of the first capacitor, the second target voltage of the second capacitor, and the third target voltage of the energy storage module, respectively, comprises:

3. The three-phase power conversion circuit according to claim 2, wherein the first bidirectional switch, the second bidirectional switch, and the third bidirectional switch remain turned off in a section in which a difference between a maximum phase voltage and a middle phase voltage of the three-phase ac power supply is smaller than a first voltage value and a difference between the middle phase voltage and a minimum phase voltage of the three-phase ac power supply is smaller than a second voltage value.

4. The three-phase power conversion circuit according to claim 2, wherein in a section where a difference between a maximum phase voltage and an intermediate phase voltage of the three-phase ac power is smaller than a first voltage value and a difference between the intermediate phase voltage and a minimum phase voltage of the three-phase ac power is smaller than a second voltage value, a third duty ratio is calculated from the third target voltage, the actual measurement value of the output voltage of the energy storage module, and the current signal of the three-phase ac power to control the bidirectional switch assembly.

5. The three-phase power conversion circuit according to any one of claims 2 to 4, wherein the first voltage value is a first target voltage of the first capacitor or is the first capacitor voltage.

6. The three-phase power conversion circuit according to any one of claims 2 to 4, wherein the second voltage value is a second target voltage of the second capacitor or is the second capacitor voltage.

7. The three-phase power conversion circuit according to claim 1, wherein the dc load module comprises the first dc load and the second dc load, and the control module is specifically configured to:

8. The three-phase power conversion circuit according to claim 1, wherein the dc load module comprises the first dc load and the third load, and the control module is specifically configured to:

9. The three-phase power conversion circuit according to claim 1, wherein the dc load module comprises the second dc load and the third load, and the control module is specifically configured to:

10. The three-phase power conversion circuit according to claim 1, wherein the dc load module comprises the first dc load, the second dc load and the third load, and the control module is specifically configured to:

11. The three-phase power conversion circuit according to claim 1, wherein the first bidirectional switch, the second bidirectional switch, and the third bidirectional switch each comprise two power switching transistors connected in anti-parallel.

12. The three-phase power conversion circuit according to claim 1, wherein the first bidirectional switch, the second bidirectional switch and the third bidirectional switch each comprise two power switching tubes connected in reverse series, and the two power switching tubes are connected in reverse parallel with a diode.

13. The three-phase power conversion circuit according to claim 1, wherein the first bidirectional switch, the second bidirectional switch, and the third bidirectional switch each comprise a fourth leg, a fifth leg, and a sixth leg that are connected in parallel with each other, each of the fourth leg and the sixth leg comprises two diodes connected in series with each other, and the fifth leg comprises a power switch tube.

14. The circuit control method is applied to a three-phase power supply conversion circuit, wherein the three-phase power supply conversion circuit comprises a rectification module, an energy storage module and a direct current load module, the rectification module comprises a three-phase rectification bridge and a two-way switch assembly, and the three-phase rectification bridge comprises a first bridge arm, a second bridge arm and a third bridge arm which are mutually connected in parallel; the bidirectional switch assembly comprises a first bidirectional switch, a second bidirectional switch and a third bidirectional switch, one end of the first bidirectional switch is connected with the midpoint of the first bridge arm, one end of the second bidirectional switch is connected with the midpoint of the second bridge arm, and one end of the third bidirectional switch is connected with the midpoint of the third bridge arm; the energy storage module is connected with the direct current output end of the rectifying module and comprises a first capacitor and a second capacitor which are connected in series, and the other end of the first bidirectional switch, the other end of the second bidirectional switch and the other end of the third bidirectional switch are connected between the first capacitor and the second capacitor; the direct current load module comprises at least two of a first direct current load, a second direct current load and a third load, wherein the first direct current load is connected with the first capacitor in parallel, the second direct current load is connected with the second capacitor in parallel, and the third load is connected with the energy storage module in parallel; the circuit control method is characterized by comprising the following steps:

15. The circuit control method according to claim 14, wherein the obtaining the current signal of the three-phase ac power supply, the first capacitor voltage, and the second capacitor voltage, and outputting a control signal to the bidirectional switch assembly so that the voltage reaching the first capacitor is maintained at least two of the first target voltage, the voltage reaching the second capacitor is maintained at the second target voltage, and the voltage reaching the energy storage module is maintained at the third target voltage, respectively, according to at least two of the first target voltage of the first capacitor, the second target voltage of the second capacitor, and the third target voltage of the energy storage module, respectively, comprises:

16. The circuit control method according to claim 15, wherein the first bidirectional switch, the second bidirectional switch, and the third bidirectional switch are kept turned off in a section in which a difference between a maximum phase voltage and an intermediate phase voltage of the three-phase alternating-current power supply is smaller than a first voltage value and a difference between the intermediate phase voltage and a minimum phase voltage of the three-phase alternating-current power supply is smaller than a second voltage value.

17. The circuit control method according to claim 15, wherein in a section in which a difference between a maximum phase voltage and an intermediate phase voltage of the three-phase alternating current power supply is smaller than a first voltage value and a difference between the intermediate phase voltage and a minimum phase voltage of the three-phase alternating current power supply is smaller than a second voltage value, a third duty ratio is calculated from the third target voltage, the actual measured value of the output voltage of the energy storage module, and the current signal of the three-phase alternating current power supply to control the bidirectional switch assembly.

18. The circuit control method according to any one of claims 15 to 17, wherein the first voltage value is a first target voltage of the first capacitor or is the first capacitor voltage.

19. The circuit control method according to any one of claims 15 to 17, wherein the second voltage value is a second target voltage of the second capacitor or is the second capacitor voltage.

20. The circuit control method according to claim 14, wherein the dc load module includes the first dc load and the second dc load, and the circuit control method specifically includes:

21. The circuit control method according to claim 14, wherein the dc load module includes the first dc load and the third load, the circuit control method specifically comprising:

22. The circuit control method according to claim 14, wherein the dc load module includes the second dc load and the third load, the circuit control method specifically comprising:

23. The circuit control method according to claim 14, wherein the dc load module includes the first dc load, the second dc load, and the third load, the circuit control method specifically comprising:

24. A circuit board, characterized in that: a three-phase power conversion circuit as claimed in any one of claims 1 to 13.

25. An operation control device comprising at least one processor and a memory for communication connection with the at least one processor; the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the circuit control method of any one of claims 14 to 23.

26. An air conditioner comprising the wiring board according to claim 24 or comprising the operation control device according to claim 25.

27. A computer-readable storage medium storing computer-executable instructions for causing a computer to execute the circuit control method according to any one of claims 14 to 23.